L-Carnitine
Also known as: Carnitine, L-Carnitine Tartrate, Acetyl-L-Carnitine, ALCAR
L-Carnitine is a conditionally essential amino acid that transports long-chain fatty acids into mitochondria for energy production. It plays a critical role in fat metabolism and energy generation. Acetyl-L-Carnitine (ALCAR) is a form that crosses the blood-brain barrier and supports cognitive function.
Benefits
Supports fat metabolism and energy production during exercise. May improve exercise performance and reduce fatigue. Supports cardiovascular health. Acetyl-L-Carnitine may improve cognitive function and brain health. May support muscle recovery. Helps convert fat to energy. May reduce fatigue in certain conditions.
Recommended Dosage
No established RDA. Common supplement doses: 500–2,000 mg daily (2–3 grams for L-Carnitine Tartrate before exercise). ALCAR typically 500–2,000 mg daily. Upper limit: Generally considered safe up to 4 grams daily. Take with meals containing carbohydrates and protein for optimal absorption.
Food Sources
Red meat (beef, lamb), poultry (chicken, turkey), fish, eggs, dairy products (milk, yogurt, cheese), nuts, seeds, tempeh.
Side Effects
Well-tolerated at recommended doses. Mild side effects: nausea, stomach cramps, diarrhea, vomiting (especially with carnitine tartrate). May cause body odor or fishy smell due to metabolism. Rare: muscle weakness in those with certain genetic conditions.
Interactions
May enhance effects of blood-thinning medications (slight increase in anticoagulant effect). Anticonvulsants may increase carnitine requirements. No major adverse interactions at recommended doses. Works synergistically with CoQ10 and B vitamins.
Warnings
Those with kidney disease should monitor levels (carnitine accumulation risk). People with certain genetic carnitine disorders should avoid. Pregnant and breastfeeding women should use standard dietary sources. Those on warfarin should monitor carnitine levels. May worsen depression in some individuals.
Deficiency Symptoms
Muscle weakness and fatigue. Poor exercise tolerance and reduced performance. Cardiomyopathy and heart dysfunction (severe deficiency). Encephalopathy and neurological symptoms. Hypoglycemia. Growth delay in children.
Frequently Asked Questions
What are the benefits of L-Carnitine?▼
Supports fat metabolism and energy production during exercise. May improve exercise performance and reduce fatigue. Supports cardiovascular health. Acetyl-L-Carnitine may improve cognitive function and brain health. May support muscle recovery. Helps convert fat to energy. May reduce fatigue in certain conditions.
What is the recommended dosage for L-Carnitine?▼
No established RDA. Common supplement doses: 500–2,000 mg daily (2–3 grams for L-Carnitine Tartrate before exercise). ALCAR typically 500–2,000 mg daily. Upper limit: Generally considered safe up to 4 grams daily. Take with meals containing carbohydrates and protein for optimal absorption.
What foods contain L-Carnitine?▼
Red meat (beef, lamb), poultry (chicken, turkey), fish, eggs, dairy products (milk, yogurt, cheese), nuts, seeds, tempeh.
What are the side effects of L-Carnitine?▼
Well-tolerated at recommended doses. Mild side effects: nausea, stomach cramps, diarrhea, vomiting (especially with carnitine tartrate). May cause body odor or fishy smell due to metabolism. Rare: muscle weakness in those with certain genetic conditions.
What are the symptoms of L-Carnitine deficiency?▼
Muscle weakness and fatigue. Poor exercise tolerance and reduced performance. Cardiomyopathy and heart dysfunction (severe deficiency). Encephalopathy and neurological symptoms. Hypoglycemia. Growth delay in children.
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Supplement Disclaimer
This supplement information is for educational purposes only and should not replace professional medical advice. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease. Always consult with a healthcare provider before starting any supplement, especially if you are pregnant, nursing, taking medications, or have a medical condition.